Wiper device

ABSTRACT

A wiper device is provided that suppresses plastic deformation of a blade rubber of a wiper blade without wasting power of a battery installed to a vehicle. A wiper device is equipped with wiper blades that wipe a vehicle front glass, a wiper motor that swings the wiper blades in alternating between an upper turn position and a lower turn position by accompanied rotation of the output shaft, and a control unit that controls the wiper motor. In a case of the vehicle ignition switch being ON or OFF, the control unit controls the wiper motor such that from a stopped position where the wiper blades are located, the wiper blades are swung in a specific range of between a first stopping position and a second stopping position, and then stopped.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of, and claims domesticpriority to, U.S. patent application Ser. No. 13/762,407, filed Feb. 8,2013, which claims priority under 35 USC 119 from Japanese PatentApplication No. 2012-027704 filed Feb. 10, 2012. The presentcontinuation application hereby incorporates by reference all documentsreferenced above.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a wiper device, and in particular to awiper device that suppresses plastic deformation of a blade rubber of awiper blade.

Related Art

In a wiper device for wiping a vehicle windshield, a wiper blade isstopped at a specific location at a lower portion of the vehiclewindshield when not being operated.

The stationary wiper blade is pressed against the front windshield by aspring provided in a wiper arm that connects a wiper motor that operatesthe wiper device and the wiper blade. Thus, when the wiper device is notoperated for a long duration, there is a concern that the blade rubberof the wiper blade pressed against the front windshield might undergoplastic deformation.

Japanese Patent No. 4038016 (Patent Document 1) for example discloses awiper device that moves a wiper blade to mutually different stoppingpositions of P1 or P2 every day when the wiper device has not been usedfor a duration of 1 month.

In the wiper device disclosed in Patent Document 1 control is performedso that the wiper device moves the wiper blade to the P1 or the P2 whenthe vehicle is not being driven, and so a vehicle installed computer andwiper motor are operated without starting the vehicle engine, anunfavorable condition when generating power with an alternator. There isaccordingly an issue that power stored in the vehicle mounted battery iswasted.

SUMMARY OF THE INVENTION

The present invention is directed towards addressing the above issue,and an object of the present invention is to provide a wiper device thatsuppresses plastic deformation of a blade rubber of a wiper bladewithout wasting power of a vehicle installed battery.

In order to address the above issue, a wiper device according to a firstaspect of the present invention includes: a wiper blade that wipes afront glass of a vehicle, via a wiper arm which is supported so as to becapable of swinging with respect to the vehicle, by swinging of thewiper arm; a wiper motor that includes an output shaft connected to thewiper arm through a link so as to be capable of transmitting rotationforce to the wiper arm, and that rotates the output shaft to swing thewiper blade in alternating; and a control unit that, in a case in whichan ignition switch of the vehicle is switched ON or OFF, controls thewiper motor such that the wiper blade is swung within a specific rangefrom a position where the stopped wiper blade is located at a time whenthe ignition switch is switched ON or OFF, and the wiper blade is thenstopped.

In the wiper device according to the first aspect, each time theignition switch is operated in a stop state of the wiper blade, thewiper blade is swung within the specific range from the position wherestopped the wiper blade is located. This thereby changes the mode inwhich the rubber of the wiper blade is pressed against the front glass,and so plastic deformation of the blade rubber of the wiper blade can besuppressed.

Moreover, in the wiper device of the first aspect, swinging the wiperblade, from its stopped position, within the specific range is performedaccording to operation of the ignition switch, accompanied run of thevehicle. Accordingly, the power usage of the wiper motor and the vehicleinstalled computer to change the stop position of the wiper blade can besupplemented with electricity generated by the vehicle alternator.Consequently, plastic deformation of the blade rubber of the wiper bladecan be suppressed without wasting the power of the vehicle installedbattery.

In the aspect, it is possible that the control unit controls the wipermotor such that the wiper blade is stopped in a state in which a tiltdirection of a portion of the wiper blade, that wipes the front glass,with respect to the front glass is changed to a different direction withrespect to a tilt direction of the portion of the wiper blade at thetime when the ignition switch is switched ON or OFF.

A wiper device of a second aspect is the wiper device of the firstaspect wherein: the wiper motor rotates forward and reverse the outputshaft to swing the wiper blade between an upper turn position and alower turn position, and in a case of stopping the swinging of the wiperblade between the upper turn position and the lower turn position, thewiper motor swings the wiper blade either to a first stopping positionor a second stopping position provided above the first stopping positionand stops the wiper blade; and in the case in which the ignition switchis switched ON or OFF, the control unit controls the wiper motor suchthat the wiper blade is swung and stopped at the second stoppingposition in a case in which the wiper blade is stopped at the firststopping position at the time when the ignition switch is switched ON orOFF, and the wiper blade is swung and stopped at the first stoppingposition in a case in which the wiper blade is stopped at the secondstopping position at the time when the ignition switch is switched ON orOFF.

According to this wiper device, the wiper blade that has been stoppedfrom swinging is stopped at the first stopping position or the secondstopping position. Plastic deformation of the blade rubber of the wiperblade can be suppressed by, for example, in the case in which theignition switch is operated, swinging the wiper blade within thespecific range, that is, between the first stopping position and thesecond stopping position so as to move the wiper blade to the secondstopping position when the wiper blade is stopped in the first stoppingposition.

A wiper device of a third aspect is the wiper device of the secondaspect wherein: the control unit includes a storage section that storesa history of control performed with respect to the wiper motor; and inthe case in which the ignition switch is switched ON or OFF, the controlunit controls the wiper motor such that the history stored in thestorage section is read, the wiper blade is swung and stopped at thesecond stopping position in a case in which the wiper blade was stoppedat the first stopping position by control performed at the previous timewhen the ignition switch was switched ON or OFF, and the wiper blade isswung and stopped at the first stopping position in a case in which thewiper blade was stopped at the second stopping position by controlperformed at the previous time when the ignition switch was switched ONor OFF.

According to this wiper device, the wiper blade can be stopped in adifferent mode (shape) to that controlled at the previous time, byreferring the stopping position of the wiper blade by the controlperformed at the previous time, and moving the wiper blade to a stoppingposition different from that by the control performed at the previoustime. Plastic deformation of the blade rubber of the wiper blade canaccordingly be suppressed.

A wiper device of a fourth aspect is the wiper device of the secondaspect further including a detection unit that detects, in the case inwhich the ignition switch is switched ON or OFF, the position where thestopped wiper blade is located at the time when the ignition switch isswitched ON or OFF, wherein, in the case in which the ignition switch isswitched ON or OFF, the control unit controls the wiper motor such thatthe wiper blade is swung and stopped at the second stopping position ina case in which the position of the wiper blade detected by thedetection unit is the first stopping position, and the wiper blade isswung and stopped at the first stopping position in a case in which theposition of the wiper blade detected by the detection unit is the secondstopping position.

According to this wiper device, each time the ignition switch isoperated, the stopping position of the wiper blade is ascertained(recognized), and the wiper blade is moved to a stopping positiondifferent from the ascertained stopping position. Plastic deformation ofthe blade rubber of the wiper blade can thus be suppressed.

A wiper device of a fifth aspect is the wiper device of the first aspectwherein: the wiper motor rotates forward and reverse the output shaft toswing the wiper blade between an upper turn position and a lower turnposition, and in a case of stopping the swinging of the wiper bladebetween the upper turn position and the lower turn position, the wipermotor swings the wiper blade to a stopping position and stops the wiperblade; the control unit includes a storage section that stores a historyof control performed with respect to the wiper motor; and in the case inwhich the ignition switch is switched ON or OFF, the control unitcontrols the wiper motor such that the history stored in the storagesection is read, the wiper blade is swung to an upper return positionprovided above the stopping position and thereafter is stopped at thestopping position in a case in which the wiper blade was swung to alower return position provided below the stopping position andthereafter was stopped at the stopping position by control performed atthe previous time when the ignition switch was switched ON or OFF, andthe wiper blade is swung to the lower return position and thereafter isstopped at the stopping position in a case in which the wiper blade wasswung to the upper return position and thereafter was stopped at thestopping position by control performed at the previous time when theignition switch was switched ON or OFF.

According to this wiper device, each time the ignition switch isswitched ON or OFF the wiper blade is stopped in the original stoppingposition after moving the wiper blade within the specific range. Plasticdeformation of the blade rubber of the wiper blade can accordingly besuppressed, and the wiper blade in the stop state can also always bedisposed in a constant (same) position.

A wiper device of a sixth aspect is the wiper device of the fifth aspectwherein: a separation between the stopping position and the upper returnposition and a separation between the stopping position and the lowerreturn position are a distance such that an angle of a portion of thewiper blade, that wipes the front glass, with respect to the front glasscan be changed by the wiper blade being moved by the amount of theseparation.

According to this wiper device, plastic deformation of the blade rubberof the wiper blade can be suppressed since the angle of the portion ofthe wiper blade that wipes the front glass can be changed withcertainty.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is a schematic diagram illustrating a configuration of a wiperdevice according to a first exemplary embodiment of the presentinvention;

FIG. 2 is a cross-section, including a front glass, of a wiper blade ofa wiper device according to the first exemplary embodiment of thepresent invention in a first stopping position and a second stoppingposition;

FIG. 3 is a flow chart illustrating control of a wiper device accordingto the first exemplary embodiment of the present invention;

FIG. 4 is a schematic diagram illustrating a configuration of a wiperdevice according to a second exemplary embodiment of the presentinvention;

FIG. 5 is a cross-section, including a front glass, of a wiper blade ofa wiper device according to the second exemplary embodiment of thepresent invention in a stopping position;

FIG. 6 is a flow chart illustrating control of a wiper device accordingto the second exemplary embodiment of the present invention; and

FIG. 7 is a diagram illustrating a detection unit of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION First Exemplary Embodiment

Explanation follows regarding a wiper device according to a firstexemplary embodiment of the present invention, with reference to thedrawings.

FIG. 1 is a schematic diagram illustrating a configuration of a wiperdevice 10 according to the present exemplary embodiment. The wiperdevice 10 is, for example, employed for wiping a front glass(windshield) 12 provided at a vehicle such as a passenger car. The wiperdevice 10 includes a pair of wipers 14 and 16, a wiper motor 18, a linkmechanism 20, and a control unit 22.

The wipers 14 and 16 are respectively configured with wiper arms 24 and26, and wiper blades 28 and 30. A base end portion of each of the wiperarms 24 and 26 is fixed respectively to pivot shafts 42 and 44,described later, and the wiper blades 28 and 30 are respectively fixedto leading end portions of the wiper arms 24 and 26.

In the wipers 14 and 16, the wiper blades 28 and 30 move in alternating(opposite directions) over the front glass 12 accompanied swinging(rotating) of the wiper arms 24 and 26, and the wiper blades 28 and 30wipe a surface of the front glass 12.

The wiper motor 18 includes an output shaft 32 that is forward andreverse rotatable through a reduction mechanism 52 configured mainly byworm gears. The link mechanism 20 includes a crank arm 34, a first linkrod 36, a pair of pivot levers 38 and 40, the pair of pivot shafts 42and 44, and a second link rod 46.

One end side of the crank arm 34 is fixed to the output shaft 32, andthe other end side of the crank arm 34 is connected to one end side ofthe first link rod 36 so as to be capable of rotating. Another end sideof the first link rod 36 is connected to a location of the pivot lever38, which location is nearer to an end of the pivot lever 38 that isdifferent from an end of the pivot lever which end having the pivotshaft 42, and is connected so as to be capable of rotating. The two(both) ends of the second link rod 46 are respectively in rotatablemanner connected to the end of the pivot lever 38 that is different fromthe end of the pivot lever which end having the pivot shaft 42, and toan end of the pivot lever 40 that end corresponds to this end of thepivot lever 38 that is different.

The pivot shafts 42 and 44 are pivotally supported by pivot holders, notshown in the drawings, provided to the vehicle body. The wiper arms 24and 26 are respectively fixed, via the pivot shafts 42 and 44 to theends respectively having pivot shafts 42 and 44 of the pivot levers 38and 40.

In the wiper device 10 according to the present exemplary embodiment,when the output shaft 32 is forward and reverse rotated with a firstswing (rotating) range θ1, the rotation force of the output shaft 32 istransmitted through the link mechanism 20 to the wiper arms 24 and 26,and the wiper blades 28 and 30 move in alternating (opposite directions)over the front glass 12 between upper turn positions P1 and lower turnpositions P2 as the wiper arms 24 and 26 swing in alternating (oppositedirections).

In the wiper device 10, when the output shaft 32 forward and reverserotates with a second swing range θ2, the wiper blades 28 and 30 movebetween the lower turn positions P2 and first stopping positions P3 eachof which is lower than the lower turn position P2 as the wiper arms 24and 26 swing in alternating (opposite directions).

In the present exemplary embodiment, the wiper blades 28 and 30 movebetween the lower turn positions P2 and the first stopping positions P3in a case in which the movement in alternating of the wiper blades 28and 30 between the upper turn positions P1 and the lower turn positionsP2 for wiping the front glass is ended (finished), so for convenience,each area between the lower turn position P2 and the first stoppingposition P3 is as a storage area P5.

When the output shaft 32 is forward and reverse rotated with a thirdswing range θ3, the wiper blades 28 and 30 are moved between the firststopping positions P3 and second stopping positions P4 as the wiper arms24 and 26 swing in alternating.

In the wiper device 10 according to the present exemplary embodiment, asillustrated in FIG. 1, the crank arm 34 and the first link rod 36 form astraight line shape when the wiper blades 28 and 30 are positioned inthe first stopping positions P3.

The control unit 22 is connected to the wiper motor 18 in order tocontrol the rotation of the wiper motor 18.

The control unit 22 is, for example, configured including an inputcircuit, an ECU, a drive circuit, and a memory for storing history ofwiper control, and is connected to an ignition switch 48 that in an ONstate supplies power to an ignition system of a vehicle internalcombustion engine, and to a wiper switch 50.

In the present exemplary embodiment, each time the ignition switch 48has been switched ON or OFF, the control unit 22 is given notificationof that the ignition switch 48 is switched ON or OFF. The control unit22 controls the wiper motor 18 each time the ignition switch 48 has beenswitched ON or OFF so as to swing the wiper (wiper blades 28 and 30)within a specific range from its stopping position, and then stop thewiper.

History of control performed on the wiper motor 18 each time theignition switch 48 has been switched ON or OFF is stored in the memoryprovided to the control unit 22. The control unit 22 refers (reads) thehistory stored in the memory (FIG. 1) when the ignition switch 48 hasbeen switched ON or OFF. The wiper motor 18 is controlled to move thewiper blades 28 and 30 to the second stopping positions P4 in a case inwhich, by control of the previous time the ignition switch 48 wasswitched ON or OFF, the wiper blades 28 and 30 were stopped in the firststopping position P3. The wiper motor 18 is controlled to move the wiperblades 28 and 30 to the first stopping position P3 in a case in which,by control of the previous time the ignition switch 48 was switched ONor OFF, the wiper blades 28 and 30 were stopped in the second stoppingpositions P4.

The wiper switch 50 is a switch that switches power supply from thevehicle battery to the wiper motor 18 ON or OFF.

The wiper switch 50 is switchable among: a low speed operation modeselection position that causes the wiper blades 28 and 30 to swing atlow speed; a high speed operation mode selection position that causesthe wiper blades 28 and 30 to swing at high speed; an intermittentoperation mode selection position that causes the wiper blades 28 and 30to swing intermittently at a specific cycle; and a storage (stop(stationary)) mode selection position. The wiper switch 50 outputs tothe control unit 22 a signal corresponding to the selection position foreach mode.

When the signal corresponding to the selection position for each mode isoutput from the wiper switch 50 to the control unit 22, the control unit22 then performs control according to the output signal from the wiperswitch 50.

FIG. 2 is a cross-section of the wiper blade 28, including the frontglass 12, at the first stopping position P3 and at the second stoppingposition P4 of the wiper device 10 according to the present exemplaryembodiment. In FIG. 2 the left hand side corresponds to upwards on thefront glass 12, and the right hand side corresponds to downwards on thefront glass 12.

When the wiper blade 28 stops in the first stopping position P3, a lipportion 56 of the rubber of the wiper blade 28 stops in a state in whichit is tilted to the left hand side, namely towards the front glass 12upper side, since the wiper blade 28 has stopped in the first stoppingposition P3 after being moved to arrive from upwards on the front glass12.

When the wiper blade 28 stops in the second stopping position P4, thelip portion 56 of the rubber of the wiper blade 28 stops in a state inwhich it is tilted to the right hand side, namely to the front glass 12lower side, since the wiper blade 28 has stopped in the second stoppingposition P4 after being moved to arrive from downwards on the frontglass 12.

The rubber of the wiper blades is a resilient (elastic) body, howeverthere is a concern that plastic deformation may occur in the rubber in acase in which the state at first stopping position P3 or the state atsecond stopping position P4 continues for a long duration, and that theability of the wiper to wipe the front glass 12 might deteriorate whensuch plastic deformation occurs.

In the present exemplary embodiment, plastic deformation in the rubberof the wiper blades 28 and 30 is suppressed by changing the stoppingpositions of the wiper blades 28 and 30 to the first stopping positionsP3 or the second stopping positions P4 each time the ignition switch 48is switched ON or OFF.

Explanation next follows regarding control of the wiper device 10according to the present exemplary embodiment. FIG. 3 is a flow chartillustrating control of the wiper device 10 according to the presentexemplary embodiment.

When the ignition switch 48 is operated, referring is made, at step 300,to the history of the record of control of the stopping positions of thewiper blades 28 and 30 when the ignition switch 48 is operated, whichhistory is stored in the memory.

At step 302, in the referred history, determination is made as towhether or not the wiper blades 28 and 30 were controlled so as to bestopped in the first stopping positions P3 at the last time (theprevious time) when the ignition switch 48 was switched ON or OFF.

When determined at step 302 is made that the wiper blades 28 and 30 werestopped in the first stopping positions P3 by control at the last timewhen the ignition switch 48 was switched ON or OFF, then at step 304,the wiper blades 28 and 30 are moved so as to be stopped at the secondstopping positions P4, and processing is ended.

When determined at step 302 is made that the wiper blades 28 and 30 werenot stopped in the first stopping positions P3 by control at the lasttime when the ignition switch 48 was switched ON or OFF, namely whendetermined that the wiper blades 28 and 30 were stopped in the secondstopping positions P4 by control at the last time when the ignitionswitch 48 was switched ON or OFF, then at step 306 the wiper blades 28and 30 are moved so as to be stopped at the first stopping positions P3,and processing is ended.

Note that configuration may be made such that determination is made atstep 302 as to whether or not the wiper blades 28 and 30 were stopped inthe second stopping positions P4 by control at the last time when theignition switch 48 was switched ON or OFF.

As explained above, according to the wiper device 10 of the presentexemplary embodiment, plastic deformation in the rubber of the wiperblades 28 and 30 can be suppressed by changing the positions of thewiper blades 28 and 30 which have been stopped in each time the ignitionswitch is switched ON or OFF.

Moreover, configuration may be made such that a detection unit (FIG. 7)is further provided that, when the ignition switch 48 is switched ON orOFF, detects the positions where the wiper blades 28 and 30 have beenstopped. The control unit 22 controls the wiper motor 18 so as torespectively move the wiper blades 28 and 30 such that the wiper blades28 and 30 are moved to the second stopping positions P4 when thepositions of wiper blades 28 and 30 which are detected by the detectionunit are in the first stopping positions P3, and such that the wiperblades 28 and 30 are moved to the first stopping positions P3 when thepositions of the wiper blades 28 and 30 which are detected by thedetection unit are in the second stopping positions P4.

There are various possible ways for detecting the positions where thewiper blades 28 and 30 have been stopped, such as providing for examplea MR (magnetoresistance) sensor to the reduction mechanism 52 of thewiper motor (FIG. 7), and detecting the stopping positions of the wiperblades 28 and 30 by detecting the positions of the wiper arms.

The stopping positions of the wiper blades 28 and 30 detected by the MRsensor or the like are the actual stopping positions of the wiper blades28 and 30 at the current point in time, enabling control so as to stopthe wiper blades 28 and 30 at stopping positions different from thestopping positions of the wiper blades 28 and 30 at the current point intime, with such control enabling deterioration by plastic deformation ofthe wiper blades 28 and 30 to be suppressed.

In the present exemplary embodiment, separately from the controlexplained in FIG. 3, the wiper blades 28 and 30 are stopped in the firststopping positions P3 or the second stopping positions P4 when the wiperswitch 50 is switched OFF. In this case, it is considered to stop thewiper blades 28 and 30 in the first stopping positions which are locatedin the lower positions on the front glass 12 in order to avoid windpressure during travel.

Or, configuration may be made such that, referring is made to thehistory of control at the last time when the ignition switch 48 wasoperated, such as in above step 300 and step 302, to determine thestopping positions of the wiper blades 28 and 30 when the wiper switch50 is switched OFF.

Note that although in the present exemplary embodiment, the secondstopping position P4 is provided between the lower turn position P2 andthe first stopping position P3, the second stopping position P4 may beprovided above the lower turn position P2, to give a sequence of secondstopping position P4, lower turn position P2 and first stopping positionP3 from upwards to downwards on the front glass 12.

In the present exemplary embodiment it is possible to provide the secondstopping position P4 above the lower turn position P2 by adjusting thesecond swing range θ2 that is the range of forward and reverse rotationof the output shaft 32 to be larger than that in the case illustrated inFIG. 1.

In such case, since the distance between the first stopping position P3and the second stopping position P4 becomes larger, tilting of therubber portions of the wiper blades 28 and 30 with respect to the frontglass 12 can be changed with certainty by moving the wiper blades 28 and30 from the first stopping position P3 to the second stopping positionP4 for example.

Moreover, in the present exemplary embodiment it is possible to providethe first stopping position P3 and the second stopping position P4between the upper turn position P1 and the lower turn position P2 bychanging the forward and reverse rotation range of the output shaft 32.

Second Exemplary Embodiment

Explanation follows regarding a wiper device according to a secondexemplary embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a configuration of a wiperdevice 100 according to the present exemplary embodiment. The wiperdevice 100 is basically the same as the wiper device 10 according to thefirst exemplary embodiment, and similar configurations to that of thewiper device 10 of the first exemplary embodiment are allocated the samereference numerals in FIG. 4 to those of the wiper device 10 accordingto the first exemplary embodiment, and explanation thereof is omitted.

The wiper device 100 according to the present exemplary embodimentdiffers from the wiper device 10 according to the first exemplaryembodiment in the provision of a control unit 220 and the stoppingposition of the wiper blades 28 and 30 based on control of the controlunit 220. Whereas in the first exemplary embodiment the wiper blades 28and 30 are stopped in one or other of the first stopping positions P3and the second stopping positions P4, in the present exemplaryembodiment, the wiper blades 28 and 30 are stopped in stopping positionsP8 that are in positions equivalent to the second stopping positions P4in the first exemplary embodiment.

In the present exemplary embodiment, when the output shaft 32 is forwardand reverse rotated with a first swing range θ1, the rotation force ofthe output shaft 32 is transmitted through the link mechanism 20 to thewiper arms 24 and 26, and the wiper blades 28 and 30 move in alternatingon the front glass 12 between the upper turn positions P1 and the lowerturn positions P2 accompanying the swinging in alternating of the wiperarms 24 and 26.

Moreover, in the present exemplary embodiment, when the output shaft 32is forward and reverse rotated with a second swing range θ2, the wiperblades 28 and 30 are moved between upper return positions P6 and lowerreturn positions P7 accompanying swinging in alternating of the wiperarms 24 and 26.

In the present exemplary embodiment, when the output shaft 32 is forwardand reverse rotated with a third swing range θ3, the wiper blades 28 and30 move between the lower return positions P7 and stopping positions P8accompanying swinging in alternating of the wiper arms 24 and 26.

Moreover, in the present exemplary embodiment, when the output shaft 32is forward-reverse rotated with a fourth swing range θ4, the wiperblades 28 and 30 move between the upper return positions P6 and thestopping positions P8 accompanying the swinging in alternating of thewiper arms 24 and 26.

In FIG. 4, the lower return position P7 of the present exemplaryembodiment corresponds to the first stopping position P3 of the firstexemplary embodiment.

In FIG. 4, the upper return position P6 of the present exemplaryembodiment corresponds to the lower turn position P2 referred to theabove, however it is possible to position the upper return position P6at a different position to the lower turn position P2 by adjusting thethird swing range θ3 and the fourth swing range θ4 that are forward andreverse rotation ranges of the output shaft 32. Moreover, it is alsopossible to provide the upper return position P6 and the lower returnposition P7 between the upper turn position P1 and the lower turnposition P2 by changing the forward and reverse rotation range of theoutput shaft 32.

In the present exemplary embodiment, the control unit 220 stores historyof control of the wiper motor 18 in a memory, and the wiper blades 28and 30 are swung to and stopped at the stopping position P8 whenswinging in alternating of the wiper blades 28 and 30 between the upperturn position P1 and the lower turn position P2 is ended (finished).

In the present exemplary embodiment, referring is made to the historystored in the memory when the ignition switch 48 has been switched ON orOFF. The wiper blades 28 and 30 are stopped at the stopping positions P8after being swung to the upper return positions P6 provided above thestopping positions P8 in a case in which the wiper blades 28 and 30 werestopped at the stopping positions P8 after being swung to the lowerreturn positions P7 by control at the last time (the previous time) whenthe ignition switch 48 was switched ON or OFF. On the other hand, thewiper blades 28 and 30 are stopped at the stopping positions P8 afterbeing swung to the lower return positions P7 in a case in which thewiper blades 28 and 30 were stopped the stopping positions P8 afterbeing swung to the upper return positions P6 by control at the last timewhen the ignition switch 48 was switched ON or OFF.

Consequently, as illustrated in FIG. 5, a cross-section of the wiperblade 28, including the front glass 12, at the stopping position of thewiper device 100 according to the present exemplary embodiment, in thepresent exemplary embodiment, the wiper blade 28 is always stopped atthe stopping position P8, and the angle of the lip portion 56 withrespect to the front glass 12 can be changed by, each time the ignitionswitch is operated, moving the wiper blade 28 from the stopping positionP8, then returning at the upper return position P6 or returning at thelower return position P7, and then going back and stopping the wiperblade 28 at the stopping position P8.

In the present exemplary embodiment, the separation between the lowerreturn position P7 and the upper return position P6 can be changed byadjusting the third swing range θ3 and/or the fourth swing range θ4 thatare the forward and reverse rotation ranges of the output shaft 32. Thisseparation needs to be a distance sufficient to obtain a change in theangle (tilt direction) of the lip portion 56, which is the portion ofeach of the wiper blades 28 and 30 that wipes the front glass 12, withrespect to the front glass 12 (in the exemplary embodiments, forexample, the tilt towards the front glass 12 upper side is changed tothe tilt towards the front glass 12 lower side).

This distance is affected by differences in the flexibility of the lipportions 56 of the wiper blades 28 and 30, the structure of portions ofthe wiper device, the curvature of the front surface of the front glass12 and/or surface treatment of the front glass 12. It is accordinglypossible to determine this distance statistically by performing testing.

Explanation follows regarding control of the wiper device 100 accordingto the present exemplary embodiment. FIG. 6 is a flow chart illustratingcontrol of the wiper device 100 according to the present exemplaryembodiment.

When the ignition switch 48 is operated, referring is made, at step 600,to the history of the record of control of the stopping positions of thewiper blades 28 and 30 when the ignition switch 48 is operated, whichhistory is stored in the memory.

At step 602, in the referred history, determination is made as towhether or not the wiper blades 28 and 30 were controlled so as to bereturned at the upper return position P6, namely, whether or not thewiper blades 28 and 30 were controlled so as to be swung from thestopping positions P8 to the upper return positions P6, thereafter to bestopped at the stopping positions P8, at the last time (the previoustime) when the ignition switch 48 was switched ON or OFF.

When determined at step 602 that, the last time the ignition switch 48was switched ON or OFF, the wiper blades 28 and 30 were controlled so asto be stopped at the stopping positions P8 after swinging from thestopping positions P8 to the upper return positions P6, then at step604, the wiper blades 28 and 30 are stopped at the stopping positions P8after swinging the wiper blades 28 and 30 from the stopping positions P8to the lower return positions P7, and processing is ended.

When determined at step 602 that, the last time the ignition switch 48was switched ON or OFF, control was not performed to stop the wiperblades 28 and 30 at the stopping positions P8 after swinging the wiperblades 28 and 30 from the stopping positions P8 to the upper returnpositions P6, namely when determined that, the last time the ignitionswitch 48 was switched ON or OFF, control was performed to stop thewiper blades 28 and 30 at the stopping positions P8 after swinging thewiper blades 28 and 30 from the stopping positions P8 to the lowerreturn positions P7, then at step 606, the wiper blades 28 and 30 arestopped at the stopping positions P8 after swinging the wiper blades 28and 30 from the stopping positions P8 to the upper return positions P6,and processing is ended.

Note that configuration may be made such that determination is made atstep 602 as to whether or not, the last time the ignition switch 48 wasswitched ON or OFF, control was performed to stop the wiper blades 28and 30 at the stopping positions P8 after swinging from the stoppingpositions P8 to the lower return positions P7.

As explained above, according to the wiper device 100 of the presentexemplary embodiment, plastic deformation of the rubber of the wiperblades 28 and 30 can be suppressed, since each time the ignition switchhas been switched ON or OFF, the wiper blades 28 and 30 are stopped atthe original stopping position after being moved with the specificrange. Moreover, in contrast to the first exemplary embodiment, thewiper blades 28 and 30 in the stop state can also always be disposed ina constant (same) position.

Moreover, in the present invention, it is not affected by the weather,irrespective of wiper blade operation such as during wet weather, sinceswinging of the wiper blades is based on switching the ignition switchON or OFF.

What is claimed is:
 1. A wiper device comprising: a wiper blade thatwipes a front glass of a vehicle, via a wiper arm which is supported soas to be capable of swinging with respect to the vehicle, by swinging ofthe wiper arm; a wiper motor that includes an output shaft connected tothe wiper arm through a link so as to be capable of transmittingrotation force to the wiper arm, and that rotates the output shaft toswing the wiper blade in alternating, the wiper motor rotating forwardand reverse the output shaft to swing the wiper blade between an upperturn position and a lower turn position; and a control unit thatincludes a storage section that stores a history of control performedwith respect to the wiper motor, wherein, in a case in which apredetermined operation of an ignition switch of the vehicle isperformed, the control unit reads the history stored in the storagesection, and based on the read history, controls the wiper motor suchthat the stopped wiper blade which is stopped in a specific range whichis set in the vicinity of the lower turn position is swung within thespecific range from a position where the stopped wiper blade is locatedat a time when the predetermined operation of the ignition switch isperformed and thereafter the wiper blade swinging within the specificrange is stopped in the specific range, and wherein an upper end and alower end of the specific range in a swinging direction of the wiperblade are set at positions which are in the vicinity of the lower turnposition, and the upper end and the lower end of the specific range areset at the positions which are nearer to the lower turn position thanthe upper turn position in the swinging direction of the wiper blade. 2.A wiper device comprising: a wiper blade that wipes a front glass of avehicle, via a wiper arm which is supported so as to be capable ofswinging with respect to the vehicle, by swinging of the wiper arm; awiper motor that includes an output shaft connected to the wiper armthrough a link so as to be capable of transmitting rotation force to thewiper arm, and that rotates the output shaft to swing the wiper blade inalternating, the wiper motor rotating forward and reverse the outputshaft to swing the wiper blade between an upper turn position and alower turn position; and a control unit that includes a storage sectionthat stores a history of control performed with respect to the wipermotor, wherein, in a case in which a predetermined operation of anignition switch of the vehicle is performed, the control unit reads thehistory stored in the storage section, and based on the read history,controls the wiper motor such that the stopped wiper blade which isstopped in a specific range which is set in the vicinity of the lowerturn position is swung within the specific range from a position wherethe stopped wiper blade is located at a time when the predeterminedoperation of the ignition switch is performed and thereafter the wiperblade swinging within the specific range is stopped in the specificrange, wherein an upper end and a lower end of the specific range in aswinging direction of the wiper blade are set at positions which are inthe vicinity of the lower turn position, and the upper end and the lowerend of the specific range are set at the positions which are nearer tothe lower turn position than the upper turn position in the swingingdirection of the wiper blade, and wherein, based on the read history, inthe case in which the predetermined operation of the ignition switch ofthe vehicle is performed, the control unit controls the wiper motor suchthat the stopped wiper blade is swung within the specific range andthereafter the wiper blade swinging within the specific range is stoppedat a position within the specific range, which is different from theposition where the stopped wiper blade is located.
 3. The wiper deviceof claim 2, wherein: in a case of stopping the swinging of the wiperblade between the upper turn position and the lower turn position, thewiper motor swings the wiper blade either to a first stopping positionwithin the specific range or a second stopping position within thespecific range, provided above the first stopping position, and stopsthe wiper blade at the first stopping position or at the second stoppingposition, based on the read history, in the case in which thepredetermined operation of the ignition switch of the vehicle isperformed, the control unit controls the wiper motor such that: in acase in which the stopped wiper blade is stopped at the first stoppingposition, the stopped wiper blade is swung within the specific range andthereafter the wiper blade swinging within the specific range is stoppedat the second stopping position, and in a case in which the stoppedwiper blade is stopped at the second stopping position, the stoppedwiper blade is swung within the specific range and thereafter the wiperblade swinging within the specific range is stopped at the firststopping position.
 4. A wiper device comprising: a wiper blade thatwipes a front glass of a vehicle, via a wiper arm which is supported soas to be capable of swinging with respect to the vehicle, by swinging ofthe wiper arm; a wiper motor that includes an output shaft connected tothe wiper arm through a link so as to be capable of transmittingrotation force to the wiper arm, and that rotates the output shaft toswing the wiper blade in alternating, the wiper motor rotating forwardand reverse the output shaft to swing the wiper blade between an upperturn position and a lower turn position; and a control unit thatincludes a storage section that stores a history of control performedwith respect to the wiper motor, wherein, in a case in which apredetermined operation of an ignition switch of the vehicle isperformed, the control unit reads the history stored in the storagesection, and based on the read history, controls the wiper motor suchthat the stopped wiper blade which is stopped in a specific range whichis set in the vicinity of the lower turn position is swung within thespecific range from a position where the stopped wiper blade is locatedat a time when the predetermined operation of the ignition switch isperformed and thereafter the wiper blade swinging within the specificrange is stopped in the specific range, wherein an upper end and a lowerend of the specific range in a swinging direction of the wiper blade areset at positions which are in the vicinity of the lower turn position,the upper end and the lower end of the specific range are set at thepositions which are nearer to the lower turn position than the upperturn position in the swinging direction of the wiper blade, and wherein,based on the read history, in the case in which the predeterminedoperation of the ignition switch of the vehicle is performed, thecontrol unit controls the wiper motor such that, when the stopped wiperblade is swung within the specific range, the wiper blade swingingwithin the specific range is returned at a return position which iswithin the specific range and is determined based on the read history.5. The wiper device of claim 4, wherein in a case of stopping theswinging of the wiper blade between the upper turn position and thelower turn position, the wiper motor swings the wiper blade to astopping position within the specific range and stops the wiper blade atthe stopping position, and based on the read history, in the case inwhich the predetermined operation of the ignition switch of the vehicleis performed, the control unit controls the wiper motor such that: thestopped wiper blade is swung to an upper return position as the returnposition, which is within the specific range and provided above thestopping position, and thereafter the wiper blade swinging within thespecific range is stopped at the stopping position, in a case in whichthe wiper blade was swung to a lower return position as the returnposition, which is within the specific range and provided below thestopping position, and thereafter was stopped at the stopping positionby control performed by the control unit at the previous time, and thestopped wiper blade is swung to the lower return position and thereafterthe wiper blade swinging within the specific range is stopped at thestopping position, in a case in which the wiper blade was swung to theupper return position and thereafter was stopped at the stoppingposition by control performed by the control unit at the previous time.